Problem: Evaluate the following expression when $d = 4$ and $c = 4$. $7$ $d$ $ + 8$ $c$ $ + 7$
Solution: Substitute $4$ for ${d}$ and $4$ for ${c}$ $ = 7{(4)} + 8{(4)} + 7 $ $ = 28 + 32 + 7 $ $ = 67$